Risk of gastric cancer after Roux-en-Y gastric bypass.

OBJECTIVE

To evaluate the risk of gastric cancer after Roux-en-Y gastric bypass (RYGB).

DESIGN

Rats randomly underwent 1 of the following: RYGB, duodenojejunal bypass (DJB), or a sham operation. Postoperatively, rats underwent a protocol of cancer induction by means of both continuous (200 ppm in tap water for 16 weeks) and intermittent (50-mg/kg intraesophageal injection, once a week, for 12 weeks) administration of N-methyl-N-nitrosourea.

SETTING

Institut de Recherche Contre les Canceurs de l'Appareil Digestif-European Institute of Telesurgery. STUDY ANIMALS: Fifty-five Fischer 344 rats.

MAIN OUTCOME MEASURES: Seventeen weeks after the operation, we performed a pathologic examination of the whole stomach in all animals to assess for the presence of cancer and/or premalignant lesions. Bilirubin concentration, gastric bacterial flora, and any other pathologic findings were also recorded.

RESULTS

In rats in the sham and DJB groups, the incidence of gastric cancer was 85% and 75%, respectively (P = .63), whereas only 23% of rats in the RYGB group developed gastric cancer (4-fold reduction; P = .002). The remnant stomach of rats in the RYGB group also showed a lower bilirubin concentration (P < .01) and a lower bacterial count (P < .05) compared with both the DJB and sham groups.

CONCLUSIONS

This study shows that RYGB reduces the risk of gastric cancer in an experimental model of dietary-induced carcinogenesis. Lack of direct contact with carcinogens, lower bile reflux, and a lower bacteria concentration in the gastric content may be responsible for these observations. These data suggest that RYGB may be a safe option for the treatment of morbid obesity even in areas with high gastric cancer incidence.